Bullet making



Jan. 19, 1965 A. H. BURNS, JR., ETAL 7 3,155,809

BULLET MAKING Original Filed Oct. 2, 1959 FIG-3 ARTHUR H BURNS, JR. Y CHARLES M. SCHRE/BER INVENTORS.

ATTORNEY United States Patent ce being capable of taking not only the riliing, but also i the mushrooming action.

The jacket may completely enclose the core, or leave a nose portion of soft core material protruding from it to make in the latter instance, a soft point type of bullet. Inany event, the jacket is designed to enable deformation largely at the nose without, separation of the jacket frornthe rest of the core. Such a jacket generally includes at least a base jacket and sometimes also includes a tip jacket, generally thinner and more easily deformed than the base jacket.

Heretofore, various modifications have been made in this general jacketed bullet construction in order to improve the expansion characteristics of this'type of bullet.

According to one modification, metal is removed from theinterior of the base jacket to provide it with longitudinally extending cuts or slits partially through it at the mouth. This arrangement has been tried with or without a tip jacket. The cuts' have been extended all the way through to indent the edge and provide spaced petals or serrations at themouth of the base jacket.

V 3,l65,8e Patented Jan. 19,1965

shaping die in cross section and the completed bullet partly in section at and adjacent the nose.

in accordance with this invention, there is provided an expanding bullet similar to the type shown in the above noted patents, but havinga base jacket constructed with special creasing and swaging at the mouth so as to achieve a splitting or at least a proclivity to splitting along predetermined lines while at the same time offering yielding but firm supportto the expanding core with a scooplike unfolding structure to avoid excessive core fragmentation and separation. This is done without cutting away and removing any part or" the much needed jacket support to give a significant improvement in uniformity of mushrooming, particularly atmaximum ranges, i.e.

at the lowest velocities. In a uncomplicated and economical way, the uniform expansion characteristics of this type of bullet are further extended so that the bullet behavior even at very low velocities has a remarkable uniformity which is comparable with that obtained at other ranges and velocities including the closest range and highest velocity.

The improvement is obtained by pinch-pleating the tapering mouth of the base jacket by means of creasing in such away as to form staves and a plurality of deeply inwardly extending folded webs, each between adjoining staves to form stave-like flanged panels at the edge of the jacket. Each folded web involves one very sharp bend, a single 180 bend, at which the metal is over? stressed to have at least a pronounced proclivity to split.-

The webs and a like number of staves form either an uninterrupted continuation'or an abutted array of each other around the circumference at the mouth from jacket metal of substantially uniform thickness circumferentially. Each stave or panel is flanged as its margins; and the staves are abutted at least at their'fianges. There is preferably a necking in and a longitudinal fracture at I the sharp bend to accomplish a pulling apart and a split,-

Such projectiles have also been constructed with a recess in the point. According to other and more complicated modifications, holes have been pierced fromone side of the point to the other, separate anvil pieces have been embedded in the point and corrugations have been tried in the tip jacket. More recently, however, such bullets have been improvedin accordance with prior U.S. Patent Nos. 2,765,738 and 2,838,000. 7

How the objects and advantages of thisiinvention are obtained will become apparent from a general discussion together with a description of specificembodiments shown in'the drawing in which:

I FIG. 1 is an elevational side View of one embodiment of the projectile according to this. invention;

FIG. 2 is a transverse cross sectional view of the embodiment of FiGURE 1 taken slightly tothe rear of line 11-11 after enlargement;

FIG. 3 is another elevational the base; p

FIG. 4 is a transverse section taken slightly to. the rear of line IVlV of'FlGURE 3 after enlargement;

PEG. 5 is'an' elevational side view in longitudinal cross side view of a still further 0 ting between the contiguous flangesbeginning at the edge itself. In other words, flanged slits preferably areformed in the jacket wall at the edge The resulting flanged and abutted stave structure of the jacket edge provides which is locked to the soft core by oneor more can 'nelures involving knurlsof the type shownin prior US section sho-winga die apparatus with a preliminary as sembly positioned therein 'for an interr ediate manu- -facturing operation for making a bullet ofthis invention;

FIG. 6 is an end view taken on line VlVl-lookirig 1 16.7 is an elevational Patenti1,730,87l, which provides an' interior portion of the jacket of decreased diameter. R I In the finished bullet, the longitudinally extending staves or panels take the form of'from three to nine, but

preferably from five to seven, and usually six, marginally flanged, longitudinally as well as circumferentially curved staves not only integral with the rest of the, jacket but. also at least conti uous, if not integral as well" with adjacent sectors. Adjoining staves are buttressed and are largely interconnected by a tapering pinch pleated structure-providing the greatest marginal fianging at the open edge of the base jacket but taperingto the least I flanging at, the root of each where the staves join the rest of the jacket. The. minimum inward extension of;

' the jacket edge and is preferably not less than about 1 /2 times theithicknessot the base jacket edge. Preferably the extension does not exceed 'abbut' five times the thick- 'ness of the base jacket material at the edgejwhich varies from about 0.010 of an inch to about from 0.015 of an inch for the small arms ammunition contemplated according to this invention. The pleated web, therefore, should extend inwardly at its leading edge to an internal diameter from about to about of an inch less than the exterior diameter at the edge of the jacket at the mouth.

Nine or less staves are desirable with the construction of this invention because, especially with smaller jacket mouth openings, more results in either shallow or too deep corrugating rather than flanging to the necessary depth. Too few, however, result either in too diluted an effect or in notching of the soft core at the nose too deeply; and usually too few staves and pleats give a predisposition to excessive irregularity in the jacket with respect to its edge and the axis of the bullet, unless special precautions are taken. Six creases were found suitable usually and these provide a hexafoil formation of the jacket mouth as shown in FIGURES 2 and 4.

tion in the degree of constraint offered the core making the jacket month more suitable for certain varieties of this type of bullet, the point of which may vary from the more sharply pointed point to the more rounded nose point.

By still further variation, including a greater softness in the core and/or greater working of the nose of the bullet, more pronounced external cusps may be formed in the pleats and some soft nose material may be extruded rearwardly into these cusps to overly them at least in part as extensions or scallops on the nose to better streamline bullets intended for effectiveness with accuracy at the greatest ranges.

Because of necking in of the jacket mouth, i.e. bending in of each stave, the entire edge of the base jacket at the nose is sloped rearwardly with respect to the'axis of the bullet to provide an outwardly flared, but unnotched and unscalloped edge including the substantially identically beveled leading edge of the pleated flange and rib forming webs. The slope is substantially at a right angle to the jacket curvature .tangent.

Upon impact this bevel provides a wedge action on the protruding nose of the bullet to advantageously initiate the outward expansion of the core in all radial directions uniformly.

This invention requires thatin the pleated region there be an abutted substantially double flange structure substantially thicker circumferentially than the greatest wall thickness of the adjacent sectors. As .shown and described, it is about double. In this region, the jacket metal is gradually deformed except at the apex or sharp inner bend of the cusp where bending is sufficiently severe to create -a single line of proclivity to splitting, leaving the flanges integralwith the staves, or to fracture the jacket along these lines.

In fabrication of the bullet in accordance with this invention, there is followed the procedure of blanking and cupping from a strip of desired base jacket metal, assembling with a slug of core material placed within the jacket cup, edge creasing to provide circumferentially spaced indentations adjacent the open edge of the cupshaped blank from which thejacket is shaped to final finished form, and swaging the. creased assembly to finish the bullet shape at its nose.

The indentations are achieved with'a pie-cut'edge creaser having a circumferential array of radial directed wings or fins corresponding in number to the number of pleats desired at the open end of the jacket. This sort of creasing turns in the open end of the jacket to form a frusto-conical shape (FIGURE 6) having a circumferentially spaced series of edge flutes and cusps at the latter of which the pleated web will be formed in the final swaging operation. According to the process of this invention, there is provided sutficient inward extension and thickness in the pleated region to make a sufliciently severe bend and thereby achieve a predetermined line of preferential splitting without any jacket cutting or diflicult jacket drawing to create grooves, indentations, or scallops.

Projectiles like those shown in FIGURES l and 3 made according to this invention include among others, bullets known as .243 Winchester grain soft point bullets, .270 Winchester grain soft point bullets, 30-30 Winchester grain soft point bullets, .308 Winchester grain soft point bullets, 30-06 Springfield 220 grain soft point bullets, and various other expanding bullets of still other calibers and weights.

' In the embodiment of FIGURE 1, the bullet has a base jacket 1 from the open edge 2 of which there protrudes a nose portion 21 of the soft core 20. Bordering the nose there is thin jacket portion 3 having the substantially full circular annular jacket edge 2 on the outside of which there are longitudinally extending parting lines indicative of the existence of uniformly distributed rather tightly closed internally projecting pinch pleats 8. The lines are seen at the apex of tiny cusps beginning at the edge 2 and tapering away from the edge to a hairline. The longitudinal extension is not great and usually is about from one to two times the average circumferential expanse of each panel 9 produced because of the internal structure better shown in FIGURE 2.

Each pinch pleat 8 consists of a pair of flanges 11 and 12 which are integral extensions of the lateral margins of the staves 9. These are abutted internally along a line 10 at which the flanges 11 and 12 are in continguity at least adjacent their inner ends at which the flanges are at least partially split from each other, however along only a very small part of the length at the inner end 13 of each pinch pleat 8. Therefore, the alternate pleats and panels form a continuous array of flanged metal staves adjacent the jacket edge 2 interrupted by no spaces.

It will be noted that at the edge 2 the thickness of the flanges 11 and 12 and thickness of the intervening staves 9 are substantially equal to make each pleat 8 an internal rib of about twice the thickness extending inwardly by more than the double thickness. The mouth portion 3 of jacket 1 tapers from least thickness at the edge 2 to maximum thickness where it adjoins the thicker rear part 4 of the base jacket where the jacket is provided with a knurl 6 forming a circumferential indentation in the thick circular cylindrical wall of the base jacket. In this instance, remotely frorn edge 2 each pleat 8 becomes not only shallower but its web thicker so that splitting by fracture at 13 occurs only at edge 2.

When the bullet of FIGURES 1 and 2 strikes its objective and has achieved substantial penetration, the flanged panels bulge outwardly to form curved scoop-shaped flutes and eventually splitting occurs at the apex all the way back between the flutes as the pleats unfold. Finally continued bulging and the concomitant fracturing is further accompanied by a bending back or rearward furling of the panels 9 which at the heaviest impact will ultimately peel back the relatively thin front end 3 .of the jacket until peeling is stopped at the thickened walls of the cylindrical jacket wall 4 adapted to take the rifling of the gun barrel.

In the embodiment of FIGURES 3 and 4, the also comprises a base jacket 1 and a soft core 20. Adjacent the base 5 of the jacket there is the relatively thick,

cylindrical "wall portion 4 having not only knurl 6 but bullet interconnected at the relatively unsplit fianges.

' pered part at the mouth of the jacket.

pered recesses or cusps in the jacket wall at the edge of r the jacket. In the absence of more severe swaging, the apex 13"of each cusp is not so severely bent and, therefore, fracturing does not occur so completely. The resulting staves 9", are more scoop-shaped and more In this embodiment, rearwardly extending substantially identical scallops 22 extend from the nose portion 21 of the core to occupy at least a part of the external'cusps. As is more provided on the relatively soft nose by drawing or extruding extensions from the core. These extend rearwardly from this portion to overlie and fill at least the most open partof any cusp space which might be formed between the staves at each pinch pleat at the base jacket edge. This scalloping of the core provides a more nearly smooth bullet periphery circumferentially which is desirable bal-. listically. This embodiment, even, more so than the other, avoids formation of any edges, particularly thin ones during thing which would extend forwardly into the air stream. All of the edges at 2 sweep back to streamline or overshadow the jacket edge and there is no need for chamiering. I

clearly shown in FIGURE 4, these scallops 22 tend to j 7 reduce any interruption or discontinuity occurringcircum- 1 ferentially in the bullet ogive adjacent the jacket edge 2. This form of the bullet provides a smoother exteriorby filling up at least part of the recesses.

In fabrication of the bullet, there is used an edge crimp ing device of the type shown in FIGURE 5, and-a nose shaping or swaging device of the type shown in F IGURE 7.

,In the cavity of die 4t) (Fl'GURE 5) there is a seating pin 41 upon which there is placed a jacket cup 101i con-' taining ajslug 12th of core material.

'As shown in FIGURE 5, the cup 101 has'a posterior portion of greatest thickness adjacent itsfciosed base and also a tapering anterior portion 103 terminating in the I reduced straight or unnotched edgeltiz of the open end of the cup. Similar thinness may be obtainable bya conical .fiare terminating in an enlarged cylindrical portion adjacent the edge 102. Either of these types of cups will provide a suitable thin front end 163 for making the ogival part 3 of the finished bullet jacket 1 shown in FIGURES 1-4.

The thin walled portion 1% is creased with a crimping die 59 having in its cavity '51 a suitable number, such as six, of radially arrayed equally spaced creasing fins 52.

- When the jacket cup edge 162 is thrust into cavity 51' by die 49 and its'pin 41, these fins crease the cup 1431 at 198 until there is developed the intermediate foil shaped edge and fiutes 169 shown in the hollow end structure of FIGURE 6. V I

The crimped assembly is then subjected to a further operation in a suitable female swaging die 39, the interior contour of which corresponds to the, desired finished contour for the projectile at its nose and along its sides. As punch 31 moves in during swaging, the circumference of the anterior portion 3 of the jacket 1 is reduced as the pinch pleats 8 are formed to make the final finished ta- Swaging causes Finally, the jacket is provided with one or more circumferential indentations, each a continuous 'knurl or any other suitable indentation, producing an interior portion of decreased diameter in the wall of the jacket to lar, thick and-rather deep internal webbing, which notches the core while reinforcing the paneling longitudinally.

The combination at first requires unfolding and only thereafter spreads or splits easily While simultaneously increas- A ing in resistance. This minimizes.erratic'upsetting of the core all the way up to maximum impactbecause itgives a preferred variation in thetendency of the jacket to tear at regularly spaced intervals with the least initial resist ance at the lowest velocities of impact and with the most final resistance at the end of impact at greatest demleration from highest velocity. T

At'th'e lowest velocities of impact; the finished bullet ecause of the liberal pleating and heavy webbing pro vides pre-splitting' with edge reinforcement at the very a edge ofthe' jacket. The flanged split offers the least resistance to expansion on account of accordion action while at the. same time ofie'ring' desired initial monetary delay in expansion in the initial circumferential confine-v ment to" the expanding core on accountof thefianging.

' Thus, expansion occurs readily even at distant ranges the web to fold inwardly to provide a series of ribs of double thickness projecting from the adjacent sectors without any thinning and with little, if any, Work hardening except at the inner-most fold atthe midpoint 13 or 13" of the web in the finished rib. Here the bending gives a single line of predisposition to part the flanges in the rib. As a result 'of this operation, at this stage parting lines on the exterior of the jacket are discernible by the.

inwardly to slope the edge rearwardly to grip the soft core 2i more snugly and indent itnot only at the ribs opposite the external cusps but also at the convex or scoop-shaped flanged staves 9 or 9".1 Consequently, the;edge of the jacket ideas not protrude laterally beyond the exposed nose 21. 1 j

As a result, at edge 2 the jacket is folded but is not scalloped; but according to another embodiment, rearwardly extending scallops Z ZKFIGURES 3 and 4)- are adjacent their open edge 19 at the front end of the jacketis bentl Y plete splitting occurs.

where the energy. is considerably'spent and i316 Velocity sufiicient penetration of the bullet to. occur first.

deeper than the rest of the flange action.

Along the length of the inner bend of each pinch pleatthe metal of the jacket is' severely Worked but is most severely worked and usually split at the leading edge and the least worked adjacent the root of, each stave where it joins the rest of the jacket. Each is thus made prone toprogressive splitting at extreme stages of any'degree of expansion including the severest expansion reached at higher velocities; and this together with the notches or voids the core, madeby the unfolding pleats back of the nose, controls the expansion so as to make it more uniform both circumferentially as well as radially in all directions at any given velocity. The voids takepartg 'of the deformed nose inside rather than outside the jacket to aid expansion. As the severity of impact isincreased,

-- a desired continuation and increase of resistance is offered because the part of the jacket pleats coming into action becomes shallower but broader so that at each stage the web. "there will not open initially between the moving 'staves but will continue to ofier confinement to the upsetting core until the required unfolding followed by com-j, Wherever the pleated Webisfinaliy split, progress of'the split becomes more diflicult as the Webbingtapers away and the 'degree'of metal stressing and hardeningatlthe bend decreases, :whereupon the-inf creasing bulk of expanded c'ore'material crmtinues. to en? j counter support and guidance as the staves, scoop-shaped in the form of a flute, open outwardly and finally furl back with increasing resistance.

Although the foregoing described embodiments now are belieivedto be preferred, it will be understood that various changes and modifications may be made in the embodiments described by those skilled in the art without departing from the spirit and scope of this invention.

What is claimed is:

1. The process of making a base jacketed, soft core bullet comprising the steps of assembling a slug of core material with an open mouth jacket cup having a front nose edge at the mouth and a cylindrical wall of substantially uniform thickness around said nose edge of the mouth, creasing the cup wall inwardly adjacent said mouth along uniformly circumferentially spaced lines in- V tersecting said edge, and swaging the cup adjacent said creased wall to contract said mouth and the adjacent part of said slug'to conform them to finished jacket shape about said material and to a finished bullet nose and form a pinch pleat at each of said lines by an inwardly extending bend of substantially 180 between bends each of about 90 providing a radial rib in said jacket having proclivity to splitting.

2. The process of making an expanding bullet comprising the steps of forming from relatively hard metal an elongated open mouth jacket cup thinner at the mouth than at the closed base thereof and of generally circular interior and exterior cross section at said mouth, assembling said cup with a slug of relatively malleable core material having a reduced end disposed adjacent the open '8 jacket mouth in a manner adapting said slug to form the soft core and nose of said bullet, inwardly creasing said cup mouth on a plurality of circumferentially equally spaced lines; sloping forwardly with respect to the bullet axis to form cusps around the nose edge of said cup mouth, and inwardly swaging said reduced end and cup at said mouth to shape said slug to a nose and conform said mouth thereto by substantially closing each of said cusps by a single reverse bend to form a finished bullet jacket holding said core back of said nose and having at the nose edge of said jacket a plurality of longitudinally extending staves and intervening pinch pleats corresponding in number to said cusps and forming longitudinally extending marginal flanges on the lateral edges of said staves, thereby forming staves of substantially uniform thickness 'over the bullet circumference integral with said jacket and said marginal flanges, said flanges of adjacent staves being in radial contiguity in pairs to form longitudinal ribs about twice the thickness of said staves.

References Cited by the Examiner UNITED STATES PATENTS 1,095,502 5/14 H0agland' l02-9l 2,792,618 V 5/57 Walker 29-1.23- 2,838,000 6/58 Schreiber l0291 X 2 2,932,253 4/60 Auxier 2 9--1.23 X

RICHARD H; EANES, JR.', Primary Examiner.

WHITMORE A. ,WILTZ, Examiner. 

1. THE PROCESS OF MAKING A BASE JACKETED, SOFT CORE BULLET COMPRISING THE STEPS OF ASSEMBLING A SLUG OF CORE MATERIAL WITH AN OPEN MOUTH JACKET CUP HAVING A FRONT NOSE EDGE AT THE MOUTH AND A CYLINDRICAL WALL OF SUBSTANTIALLY UNIFORM THICKNESS AROUND SAID NOSE EDGE OF THE MOUTH, CREASING THE CUP WALL INWARDLY ADJACENT SAID MOUTH ALONG UNIFORMLY CIRCUMFERENTIALLY SPACED LINES INTERSECTING SAID EDGE, AND SWAGING THE TOP ADJACENT SAID CREASED WALL TO CONTRACT SAID MOUTH AND THE ADJACENT PART OF SAID SLUG TO CONFORM THEN TO FINISHED JACKET SHAPE ABOUT SAID MATERIAL AND TO A FINISHED BULLET NOSE AND FORM A PINCH PLEAT AT EACH OF SAID LINES BY AN INWARDLY EXTENDING BEND OF SUBSTANTIALLY 180* BETWEEN BENDS EACH OF ABOUT 90* PROVIDING A RADIAL RIB IN SAID JACKET HAVING PROCLIVITY TO SPLITTING. 